What is a man-in-the-middle-attack?

What is a man-in-the-middle (MitM) attack?

Definition and explanation

A man-in-the-middle (MitM) attack occurs when a cybercriminal secretly positions themselves between two communicating systems to intercept, monitor, or manipulate the data being exchanged. The goal of a MitM attack is to steal sensitive data or disrupt communication. In a MitM attack, the attacker intercepts the data transfer between a client and a server, and then alters the data or injects malware into the communication.

Understanding one of the most dangerous cybersecurity threats

A man-in-the-middle (MitM) attack is a cyber threat where an attacker covertly inserts themselves into a communication channel between two parties, giving the illusion of a secure exchange while intercepting or manipulating the data. This allows the attacker to eavesdrop, steal sensitive information, and even manipulate data in real time without detection.

MitM attacks are a form of digital surveillance or cyber espionage, and they can compromise private information such as:

• Login credentials

• Personal identification numbers

• Online banking details

• Account details

• Credit card information

• Confidential business communication

• Other confidential information

These attacks typically exploit weaknesses in networks or web security and can be particularly effective on public or unsecured Wi-Fi connections.

A man-in-the-middle (MitM) attack is a cyberattack technique in which a third party covertly inserts themselves into a data exchange between two unsuspecting participants. Believing they are communicating privately, the two parties unknowingly share information through the attacker, who can observe the interaction, collect confidential data, and in some cases, modify the content of the messages before they reach their destination. By positioning themselves between the client and the server, the attacker can monitor and control the entire data transfer process.

The primary objective of a MitM attack is to gain access to sensitive data such as login credentials, financial information, and personal identification numbers. By intercepting this information, the attacker can commit identity theft, financial fraud, or sell the data on the dark web. In some cases, the goal may also be to disrupt communication, causing confusion and mistrust between the two parties involved.

How does a man-in-the-middle attack work?

Most MitM attacks follow a two-step process:

Interception

The attacker places themselves between the victim and the destination system, such as a bank or webshop. This is often done by exploiting insecure networks or by using techniques like DNS spoofing, IP spoofing, or rogue Wi-Fi hotspots. The victim is unaware that their communication is being routed through an attacker-controlled system.

Decryption and exploitation

Once communication is intercepted, the attacker enters the decryption phase to decrypt or manipulate the data being transmitted. This allows them to steal login details, redirect users to fake websites, or alter financial transactions. The intercepted data may then be used for identity theft, fraud, or sold on underground marketplaces.

Once the attacker intercepts the network traffic, they can alter the data being transmitted or inject malicious code into the communication. This can involve redirecting users to fake websites, modifying transaction details, or installing malware on the victim’s device. The altered or injected data can lead to significant security breaches, financial losses, and compromised personal information. By manipulating the communication, the attacker can achieve their malicious objectives without the victim’s knowledge.

Common types of MitM attacks

There are several variations of MitM attacks, each using different technical approaches. Some of the most common include:

Man-in-the-browser attacks

Attackers install malware in the victim’s web browser, often through phishing emails. This malware silently monitors and alters online activity, particularly targeting banking websites and online shopping platforms.

IP spoofing

The attacker alters the IP address of a trusted system to trick the victim into sharing sensitive data. This creates the illusion of a legitimate connection.

DNS spoofing

The attacker manipulates DNS records to redirect a user’s request to a fake website that mimics the original. Users enter sensitive data without realizing they are being deceived.

HTTP spoofing

This involves downgrading a secure Hypertext Transfer Protocol Secure (HTTPS) connection to an unsecured Hypertext Transfer Protocol (HTTP) connection. The attacker can then view or alter data in transit.

SSL hijacking

Secure Sockets Layer hijacking occurs when an attacker intercepts the encrypted session between a browser and server, allowing full access to the data being exchanged.

Email hijacking

Cybercriminals gain control of trusted email accounts, such as those used by banks or financial institutions, and use them to deceive users into sharing personal data or transferring funds.

Wi-Fi monitoring

Attackers set up fake Wi-Fi networks with names similar to trusted businesses or venues. Victims unknowingly connect to these rogue networks, exposing their online activity to the attacker.

Session hijacking

The attacker steals session cookies from a browser to gain unauthorized access to user accounts. This form of attack is commonly used against web applications that lack strong security measures.

How to prevent man-in-the-middle attacks

To reduce the risk of falling victim to a MitM attack, it’s essential to implement a combination of secure tools and smart digital habits. Here are some of the most effective prevention strategies:

Use secure connections

• Only visit websites with HTTPS in the URL bar

• Look for the padlock icon indicating a secure connection

• Ensure that the website uses a secure server by checking for HTTPS in the URL bar

• Avoid using public Wi-Fi unless protected by a VPN

Enable multi-factor authentication (MFA)

MFA provides an extra layer of security by requiring an additional form of verification beyond just a password, such as a one-time code or biometric authentication. To see why MFA is one of the most effective ways to secure your accounts, learn more about multi-factor authentication and how it protects your data.

Be cautious with phishing emails

Avoid clicking on links or downloading attachments from unexpected or suspicious emails. Phishing is a common entry point for MitM attacks. Explore our in-depth guide on phishing to better understand how these attacks work and how to avoid them.

At Moxso, we provide phishing awareness training and simulations to help employees recognize and respond to phishing attempts.

Use a VPN

A virtual private network encrypts your internet traffic, making it harder for attackers to intercept your data on public or unsecured networks. While VPNs can encrypt your internet traffic, they do not completely eliminate vulnerabilities such as HTTPS spoofing once you are on a website. Learn more about how VPNs work and why they’re essential for online security.

Install anti-malware tools

Ensure your devices are protected with up-to-date antivirus and anti-malware software that can detect and block malicious activity.

Implement awareness training

Educating employees about cybersecurity risks increases your organization’s overall resilience. Moxso offers human-centered awareness training tailored to real-world threats.

Practice good cyber hygiene

Always log out of accounts, avoid reusing passwords, and keep your software and devices updated with the latest security patches. Ensure that your mobile devices are also protected with strong passwords and up-to-date security software.

What to do if you are targeted by a MitM attack

If you believe you’ve been the target of a man-in-the-middle attack, you should act immediately:

1. Disconnect from the network

2. Change passwords for your accounts using a secure device

3. Notify your IT or security team

4. Monitor your accounts for unusual activity

5. Monitor transactions and communications for any unusual activity

6. Report the incident if required by your company’s security policy

Having a clear response plan in place is essential. An attack surface management strategy helps organizations understand their exposure and take quick action in the event of an attack.

Conclusion

Man-in-the-middle attacks are one of the most dangerous threats in modern cybersecurity. They exploit the trust between users and systems, often without any visible signs of compromise. By understanding how these attacks work and applying preventive security measures, both individuals and businesses can protect sensitive information and reduce the risk of exploitation.

At Moxso, we help organizations stay ahead of evolving threats through a combination of awareness training, phishing simulations, and cybersecurity solutions focused on people.